The present invention concerns the dynamic configuration of interface cards which support different memory sizes.
Within computers, interface cards may be added to allow the personal computer to access various peripheral devices. The interface cards generally connect to an input/output (I/O) bus. Each I/O bus has an architecture which includes physical properties and a protocol by which devices on the bus communicate. One architecture used for I/O busses is the Extended Industry Standard Architecture (EISA).
An interface card which uses EISA requires a computer, upon boot-up, to allocate a certain amount of its address space to access memory within the interface card. For example, VECTRA personal computers manufactured and distributed by Hewlett Packard Company, having a business address of 3000 Hanover Street, Palo Alto, Calif., generally allocate an address space for a 16K.times.8 erasable programmable read-only memory (EPROM) on the interface card. Alternately, computers using HP Precision Architecture system, also available from Hewlett Packard Company, generally allocate an address space for a 32K.times.8 EPROM or a 64K.times.8 EPROM.
The differing EPROM size requirement between computer systems prevent interface cards from being interchangeable between computer systems. Often, in the prior art, this has required the separate manufacture of a completely different interface card for each computer system. However, this can be extremely expensive and inefficient.
In order to avoid having to manufacture a separate type of interface card for each system, other alternatives are attempted. For example, interface cards can be designed so that when different size EPROMs are used, traces may be cut and/or jumpers may be used. However, this requires manual intervention by a user which may include powering down the computer system.
An additional issue with allocating address space for EPROMs is the possibility of conflicts when two interface cards each have an EPROM which expect to be mapped into the same fixed location in memory. In the prior art this could be overcome by, for example, using switches or removable jumpers on the interface card for changing the address to which the EPROMs were mapped in the memory of the host computer system. This, however, also requires manual intervention by a user.